The present invention relates to internal combustion engines, and more particularly to an apparatus and method of operating the same more efficiently.
Combustion engines exist in a variety of forms, but their common purpose is to provide a means to convert thermal energy into usable power. For example, an Otto four cycle engine uses the pressure resulting from combustion to drive a piston within a closed cylinder. A similar combustion chamber and piston arrangement is used in two cycle and diesel engines. The Brayton cycle used in turbine engines also uses the expansion, pressure rise, and temperature increase from combustion to create thrust and/or rotational power. The high temperature, high pressure gases are expanded across a rotating turbine to create power. Other cycles, such as the Sterling, Ericsson, Rankin, etc., are used to convert thermal energy into usable power.
Cycles such as the Otto cycle are internal combustion cycles. Cycles such as the Rankin or steam cycle are external combustion cycles. The basic processes of a cycle are heat addition, expansion, heat rejection and compression.
Internal combustion engines powered by gasoline and diesel fuels are commonly used to power vehicles and other forms of equipment. Piston type engines reciprocate pistons engaged to crankshafts and commonly use two or four strokes per cycle in their operation. Two cycle internal combustion engines generally mix the lubricating oil with gasoline (or other form of fuel) and employ only a compression stroke to compress the fuel mixture and a firing stroke subsequent to fuel ignition in the combustion chamber. Four cycle piston and rotary engines generally do not mix the lubrication oil with the fuel. Instead, these engines have a compression stroke to compress a mixture of fuel and an oxidizer (such as air). The compression stroke is followed by a firing stroke in which the mixture is ignited and then an exhaust stroke which removes the combustion chamber of the hot gases. Subsequently, an intake stroke pulls in a new volume of the fuel and air mixture into the combustion chamber. A compression stroke follows and the next cycle of operation begins.
In terms of overall energy efficiency an ideal cycle would discharge the working gas at or near ambient or sink temperature. Unfortunately, known cycles discharge combustion gases or working gases at temperatures well above the ambient sink temperature (roughly 59° F. at sea level). For example, the exhaust gas temperature of an Otto cycle engine can reach a temperature in the 1200-1700° F. range. Therefore a considerable amount of energy is wasted in the form of hot exhaust gases. This problem is the result of the combustion gases losing pressure during the expansion stroke much faster than the temperature drops. The resulting pressure is too low to drive the piston while the temperature of the gas remains quite high. It is estimated that the unused power in a standard Otto cycle engine exhaust stream is nearly equal to the cylinder piston power delivered to the crankshaft. Another nearly equal amount of power is used to conduct the excess heat away from the engine via the engine cooling system.
Therefore, current engines waste a significant portion of the energy created by combustion of fuel. Both internal and external combustion engines are inefficient in the conversion of combustion energy into usable power. It is estimated that a typical automobile engine disperses more heat energy into the environment than the energy used to drive the vehicle.
Thus, there is a need for improvement in this field.